International patent application PCT/IB2009/051485, included herein by reference and published WO/2009/125360 with title “Optical pointing device having improved environmental resistance and reflected noise prevention and compensation” discloses an optical pointing device. The optical pointing device comprises a base and an actuator movable connected to the base, the actuator comprises a reflective portion on a side facing the base, and the base comprises a light source for emitting light towards the reflective portion of the actuator, a detector comprising one of more detection units for detecting at least a part of the light reflected by the reflective portion of the actuator, and a transparent element arranged between the actuator and at least one of the light source and the detection units, for providing a closed transparent housing for the light source and/or the detection units. See also, international patent application PCT/IB2009/054036, included herein by reference and published WO/2010/035170 with title “Detection system for the detection of movements of a movable object, a method of detecting movements of a movable object, and an IC having implemented therein the detection system”
Such optical pointing devices are convenient for use, e.g., for their high accuracy, and for the small form factor in which they may be made, etc. There has been an interest in processing signals produced by such an optical pointing device. For example, International patent application PCT/IB2009/053520, included herein by reference and published WO/2010/020906 with title “Method and device for processing signals from a pointing device”, describes a method for processing signals from a pointing device which may in particularly be used with such an optical pointing device. The optical pointing device used therein comprises a detector which is adapted for providing at least first and second positional signals indicating a position of the actuator with respect to the base along corresponding first and second axes. The signal processing method comprises the steps of converting the at least two positional signals into a polar coordinate signal comprising a magnitude signal, and thresholding the magnitude signal of the polar coordinate signal to provide a thresholded magnitude signal. It is also described how a conversion curve may be applied to the thresholded magnitude signal to produce a velocity magnitude signal.
Using such a method, the optical pointing device is even better suited for some applications; for example, in applications wherein, casual or small inadvertent or spurious changes to the actuator are to be ignored to obtain a higher precision and/or control for an operator of the device.
An optical pointing device, such as an optical joystick, based on the measurement of a light reflection can replace such pointing devices as the 4-ways buttons or the digital joystick. An optical joystick can is typically analog by design joystick and enables much more than 4 or 8 predefined directions; covering virtually any angle and intensity (representing how hard one presses on the joystick).
A joystick is a device that enables to control an application running on a data processing system, by tilting a component of the joystick, such as stick or a knob in different directions, e.g., in north/south/east/west directions. The tilt is converted to pointing information, which in turn may be used, e.g., in a user-interface of the application, thus controlling the movement of a pointer. The location of the pointer is interpreted through the user-interface, for example, by converting the location of the pointer at the time of specific event, e.g., a click action performed on a click-input device of the joystick, e.g., a button, as a command-input. In response to the command-input the data-processing start execution of a computer program routine associated with the command-input. For example, the command-input may be the command to start reading a file, the associated computer program routine a sequence of computer instructions to read a file from storage.
The joystick may have centralizing means to return the component into a neutral position when no force is exerted on it. For example, the centralizing means may comprise springs.
Converting a tilting angle to an input to a data processing application differentiates joysticks from others types of input devices. For example, a mouse converts motion, a track-ball rolling, and a touch pad sliding, into command-inputs. Because of the mechanical aspect of a joystick, this control feels very natural to the end-user, and can efficiently replace the navigation-keys, the track-ball, optical sensor or a mouse. Nevertheless, it is an observation of the inventors that joysticks are typically used for pointing tasks.